Lipid peroxidation and generation of hydrogen peroxide in frozen-thawed ram semen cryopreserved in extenders with antioxidants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cytotoxic effect of a 35% hydrogen peroxide bleaching gel on odontoblast-like MDPC-23 cells

Objective. This study evaluated transenamel and transdentinal cytotoxic effects of a bleaching gel on the MDPC-23 cell line.Study design. Discs obtained from bovine incisors were placed in a metallic device to simulate an in vivo pulp chamber. Groups were formed according to the enamel surface treatment: G1: 35% H(2)O(2) bleaching gel; G2: 35% H2O2 bleaching gel + halogen light; G3: halogen light; and G4: control. Cell metabolism was evaluated by the methyltetrazolium assay and cell morphology by scanning electron microscopy.Results. Cell metabolism decreased by 31.7%, 41.6%, and 11.5% in G1, G2, and G3, respectively. Cytotoxic effects observed in G2 were significantly more severe compared with G3 and G4. In G1 and G2, a smaller number of viable cells with major morphologic alterations remained adhered to dentin.Conclusion. The bleaching gel associated with light presented transenamel and transdentinal cytotoxic effects characterised by direct damage to odontoblasts and decrease of their metabolic activity. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: 458-464)

Bacteria-derived hydrogen sulfide promotes IL-8 production from epithelial cells

Hydrogen Sulfide (H(2)S) a volatile Sulfur compound, is implicated as a cause of inflammation. especially when it is produced by bacteria colonizing gastrointestinal organs However, It IS Unclear if H(2)S produced by periodontal pathogens affects the inflammatory responses mediated by oral/gingival epithelial cells Therefore. the aims of this Study were (1) to compare the in vitro production of H(2)S among. 14 strains of Oral bacteria and (2) to evaluate the effects of H(2)S on inflammatory response induced in host oral/gingival epithelial cells Porphyromonas gingivalis (Pg) produced the most H(2)S in Culture, Which, in turn resulted in the promotion of proinflammatory cytokine IL-8 from both gingival and Oral epithelial cells The up-regulation of IL-8 expression was reproduced by the exogenously applied H(2)S Furthermore. the Mutant Strains of Pg that do not produce major Soluble Virulent factors. ie gingival, still showed the Production of H(2)S. as well as the promotion of epithelial IL-8 production. which was abrogated by H(2)S scavenging reagents These results demonstrated that Pg produces a concentration of H(2)S capable of Up-regulating-IL-8 expression induced in gingival and oral epithelial cells, revealing a possible mechanism that may promote the inflammation in periodontal disease (C) 2009 Elsevier B.V. All rights reserved

Cardiovascular responses to hydrogen peroxide into the nucleus tractus solitarius

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inhibition of central angiotensin II-induced pressor responses by hydrogen peroxide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Endogenous hydrogen peroxide in the hypothalamic paraventricular nucleus regulates sympathetic nerve activity responses to L-glutamate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

TIME-COURSE DIFFUSION of HYDROGEN PEROXIDE USING MODERN TECHNOLOGIES

The concern with the hydrogen penetration towards the pulp can be observed on the literature by the great number of papers published on this topic; Those measurements often uses chemical agents to quantify the concentration of the bleaching agent that cross the enamel and dentin. The objective of this work was the quantification of oxygen free radicals by fluorescence that are located in the interface between enamel and dentin. It was used to accomplish our objectives a Ruthenium probe (FOXY R - Ocean Optics(R)) a 405nm LED, a bovine tooth and a portable diagnostic system (Science and support LAB - LAT - IFSC/USP). The fluorescence of the probe is suppressed in presence of oxygen free radicals in function of time. The obtained results clearly shows that the hydrogen peroxide when not catalyzed should be kept in contact with the tooth for longer periods of time.

Preparative droplet counter-current chromatography for the separation of the new nor-seco-triterpene and pentacyclic triterpenoids from Qualea parviflora

The methanolic extract of the bark of the medicinal plant Qualea parviflora (Vochysiaceae) contains new nor-seco-triterpene and pentacyclic triterpenoids. They were separated in a preparative scale using droplet counter-current chromatography. The optimum solvent used was composed of a mixture of CHCl3/MeOH/H2O (43:37:20, v/v) in the descending mode and led to a successful separation of the new compound 28-nor-17, 22-seco-2 alpha, 3 beta, 19, 22, 23-pentahydroxy-Delta(12)-olecinane, besides the known triterpenoids bellericagenin B, bellericaside B and arjunglucoside I. Identification was performed by ESI-MS, H-1 NMR and C-13 NMR analyses.

Application of preparative high-speed counter-current chromatography for the separation of flavonoids from the leaves of Byrsonima crassa Niedenzu (IK)

The methanolic extract of the leaves of the medicinal plant Byrsonima crassa (Malpighiaceae) contain flavonoids with antioxidant activity. They were separated in a preparative scale using high-speed counter-current chromatography. The optimum solvent system used was composed of a mixture of ethyl acetate-n-propanol-water (140:8:80 (v/v/v)) and led to a successful separation between monoglucosilated flavonoids (quercetin-3-O-alpha-L-arabinoside, quercetin-3-O-beta-D-galactoside) and the biflavonoid amentoflavone in only 3.5 h. The purities of quercetin-3-O-alpha-L-arabinoside (95 mg), quercetin-3-O-beta-D-galactoside (16 mg) and the biflavonoid amentoflavone (114 mg) were all isolated at purity over 95%. Identification was performed by H-1 NMR, C-13 NMR and UV analyses. (C) 2004 Published by Elsevier B.V.

Effect of a leukotriene inhibitor (MK886) on nitric oxide and hydrogen peroxide production by macrophages of acutely and chronically stressed mice

We evaluated the effect of a leukotriene inhibitor (MK886) on nitric oxide (NO) and hydrogen peroxide (H2O2) production by peritoneal macrophages of mice subjected to acute and chronic stress. Acute stress was induced by keeping mice immobilized in a tube for 2 h. Chronic stress was induced over a 7-day period by the same method, but with increasing duration of immobilization. The effects of MK886 were investigated in-vitro after incubation with peritoneal macrophages, and in-vivo by submitting mice to stress and treating them daily with MK886. Supernatants of macrophage cultures were collected for NO determination and adherent cells were used for H2O2 determination. Macrophages from mice submitted to acute or chronic stress showed no alterations in H2O2 production. However, macrophages of acutely and chronically stressed mice showed inhibition of NO after incubation with MK886 in-vitro. Administration of MK886 to chronically stressed mice increased generation of H2O2 and inhibited production of NO. Our data suggest an important role of leukotrienes in NO synthesis, which is important in controlling replication of several infectious agents, mainly in stressed and immunosuppressed animals.

Metallomic study on plasma samples from Nile tilapia using SR-XRF and GFAAS after separation by 2D PAGE: initial results

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analytical approach to the metallomic of Nile tilapia (Oreochromis niloticus) liver tissue by SRXRF and FAAS after 2D-PAGE separation: Preliminary results

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)